Mesoscale Discussion 1047

Issued

Jun 21, 2021, 11:35 AM CDT (16:35 UTC)

Expired

Jun 21, 2021, 1:00 PM CDT

In force

85 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch possible

Chance of a watch

60%

The Nashville radar (KOHX), 66 km from the middle of the area, began a volume at 16:37 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

• Severe Thunderstorm Watch 301Jun 21, 12:50 PM CDT

897 
ACUS11 KWNS 211636
SWOMCD
SPC MCD 211635 
WVZ000-KYZ000-TNZ000-MOZ000-ARZ000-211800-

Mesoscale Discussion 1047
NWS Storm Prediction Center Norman OK
1135 AM CDT Mon Jun 21 2021

Areas affected...Portions of eastern Kentucky and northern Tennessee

Concerning...Severe potential...Watch possible 

Valid 211635Z - 211800Z

Probability of Watch Issuance...60 percent

SUMMARY...Storms along a cold front are expected to become more
organized through the afternoon with a threat for some large hail
and damaging winds.

DISCUSSION...Storms have developed along the cold front from
northern Kentucky into northeast Arkansas with some additional
development occurring in the unstable airmass ahead of this
activity. Mid-level flow is weaker in this region (~30-35 kts per
area VWP) which yields around 20 to 25 knots of effective shear
given the southwesterly surface winds. Therefore, storms have
struggled to become organized thus far. However, the airmass ahead
of this front is very unstable with MLCAPE around 2500 J/kg and
increasing with surface dewpoints in the low to mid 70s. This
instability and moderately steep mid-level lapse rates (~7 C/km per
BNA 12Z RAOB) will support rapid updraft growth which may pose a
threat for isolated damaging wind and large hail. As storms congeal,
they may become better organized which could support a greater wind
damage threat. If this occurs, a watch may need to be considered
across at least parts of northern Tennessee and eastern Kentucky.

..Bentley/Hart.. 06/21/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...RLX...MRX...JKL...LMK...OHX...PAH...MEG...

LAT...LON   37678659 38148517 38148248 37938223 37618218 36598373
            36068508 35458672 35488801 35608963 35829050 36029074
            37018860 37678659

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The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.